The Facts

AIDS (acquired immune deficiency syndrome) was first recognized in North America in the early 1980s. It is caused by a virus known as HIV (human immunodeficiency virus). HIV infection has become a worldwide epidemic. As of 2013, the World Health Organization (WHO) stated there were 35 million people currently infected with the virus.

HIV is more common among certain populations at risk, such as people who inject illicit drugs, and bisexual and gay men. HIV infections are also increasing among women, Aboriginal peoples, and African and Caribbean communities.


The virus can be found in the blood, semen, vaginal fluid, and breast milk of infected people. HIV is also found in saliva, sweat, and tears, though not in high enough amounts to transmit the virus to another person. There are no known cases of anyone catching HIV through sneezing, shaking hands, or from toilet seats or mosquito bites.

The two most common ways to be infected with HIV in North America are through unprotected sex and sharing needles. HIV may be transmitted through unprotected heterosexual or homosexual, vaginal, anal, or oral sex. Although the risk of infection is lower with oral sex, it is still important to use protection during oral sex, such as a dental dam (a piece of latex to cover the vagina during oral sex) or a condom. HIV can also be passed on through perinatal infection, where mothers who have HIV are at risk of giving the disease to the baby during birth. The risk of perinatal infection is declining with new treatments. Breast-feeding by an infected mother can also transmit HIV.

Once HIV enters the bloodstream, it takes over cells vital to the immune response, known as CD4+ lymphocytes. The virus then inserts its own genes into the cell, turning it into a miniature factory that produces more copies of the virus. Slowly, the amount of virus in the blood goes up and the number of healthy CD4+ cells goes down. The destruction of CD4+ cells interferes with the body's ability to fight off infections and other diseases.

Symptoms and Complications

Symptoms of HIV infection appear 2 to 12 weeks after exposure. At this point the virus begins rapidly taking over immune cells in the blood. The symptoms of this phase are flu-like and include:

  • diarrhea
  • fatigue or weakness
  • fever
  • headache
  • joint pain
  • night sweats
  • rash
  • swollen glands
  • weight loss
  • yeast infections (of the mouth or vagina) that last a long time or occur frequently

When the symptoms begin to appear, the person with HIV is very infectious. The symptoms usually go away within a week to a month, and the person will feel fine again. However, the symptoms may return from time to time. The symptoms of HIV are similar to symptoms of other diseases. The only way to know for sure whether you are HIV-positive is to be tested. After infection with HIV, it can take 3 months for antibodies to the virus to be detectable in the blood. On average, it takes about 22 days to develop antibodies. This is called seroconversion. After seroconversion occurs, the virus can be detected using a blood test.

After the initial symptoms go away, the body's immune system tries to control the virus. The immune system can keep the virus at bay for a while, but it can't completely get rid of it. Many people will feel fine for years before their immune system weakens and they develop AIDS. Without treatment, about half of HIV-positive people develop AIDS within 10 years of infection. Some people develop AIDS within a few years of infection. A few, called long-term non-progressors, do not develop AIDS until much later. Many factors affect the timeframe to develop AIDS, including medications and the person's general health and lifestyle.

AIDS is a term applied to advanced HIV disease. AIDS is defined as having HIV and an opportunistic infection (an infection by a microorganism that ordinarily does not cause disease unless the immune system is weakened) normally associated with AIDS. These infections can be bacterial, fungal, viral, or parasitic. Examples of opportunistic infections include toxoplasmosis, pneumocystis pneumonia, cryptococcal meningitis, progressive multifocal leukoencephalopathy (PML), cryptosporidium, cytomegalovirus, and Mycobacterium avium complex (MAC). With the use of better medications to treat HIV, the risk of opportunistic infections has dropped over the years; however, people with AIDS will usually need to take medications (such as antibiotics) to prevent opportunistic infections.

People who have AIDS are also more likely to develop cancer, especially cancers of the immune system (lymphomas). Another cancer common for people with AIDS is Kaposi's sarcoma, a type of cancer that causes bluish red nodules on the legs and that spreads to the lymph system. Women with AIDS are prone to developing cancers of the cervix. Gay men with HIV have higher rates of infection by HPV, a virus linked to anal cancer, and precancerous HPV strains.

Children with AIDS tend to get common childhood infections like conjunctivitis, otitis media, and tonsillitis, but they experience symptoms much worse than the infection usually causes.

Excessive weight loss or "wasting syndrome" is a problem for approximately 20% of people who have HIV infection. It is associated with an unexplained loss of 10% or more of normal body weight, plus chronic diarrhea (30 days or more) or chronic weakness with fever (30 days or more).

Most people with AIDS die from the diseases that AIDS makes them more susceptible to. The virus occasionally infects the brain, causing dementia that gets worse over time.

Making the Diagnosis

If you think you may be infected with HIV, the only way to know for sure is to be tested. Testing is voluntary and can be anonymous. Your results will remain confidential. You can be tested at your physician's office or at a sexual health clinic, many of which are run by local public health units.

HIV testing can involve two types of tests: a preliminary test that detects HIV antibodies and a final confirmatory test. If the rapid test, which requires a finger prick of blood, is reactive to HIV, a second laboratory-based test is required to determine whether someone is HIV positive. However, if the rapid test is negative, then no further testing is required.

If HIV infection is confirmed, your doctor will discuss treatment options as well as support groups and other services to help you cope. You should inform your sexual partners (past, current, and future) to protect them from developing HIV or help them get treatment if they have been infected. The laws about whether partners must be informed vary from province to province, but most provinces have developed services for notifying partners. Your doctor or provincial ministry of health may be able to help your partners get testing and treatment if needed.

Treatment and Prevention

HIV is usually treated with HAART (highly active antiretroviral therapy), a potent combination of anti-HIV medications. HAART will not cure HIV, but it can reduce the amount of virus in the blood, improve the immune system, and slow the progression of the disease. At least three medications are used together. Using multiple medications that work in different ways helps prevent the virus from becoming resistant to the treatment. The risk of resistance increases when fewer medications are used, when too low a dose is taken, or when a medication is stopped, even if this only happens for a short period of time.

It is very important to take HIV medications exactly as prescribed. If you miss a dose, take less medication than you need, or take doses at the wrong time, the medication will not work as well. Timing the medications around your meals and daily routine can be difficult. Your doctor or pharmacist can help you fit the medications into your day. They may also recommend that you use a beeper or a special medication container to keep track of doses.

Once people develop AIDS, they usually take a range of antibiotic, antiviral, and antifungal medications that other people only take for a short time while they are sick. These medications help fight off opportunistic infections. People with "wasting syndrome" may be offered various treatments according to the cause of significant weight loss. Agents such as growth hormone, anabolic steroids, and appetite stimulants are examples of medications that have been used to treat this condition.

There is a great deal of research on new treatments for HIV. Treatment information changes quickly. To keep up-to-date, talk to your doctor or pharmacist. You can also contact CATIE (the Canadian AIDS Treatment Information Exchange) for free, current, and confidential treatment information. You can reach CATIE by phone (1-800-263-1638) or on the Internet ( You can also check with your provincial Ministry of Health for information on provincial and local programs.

Anyone can become infected with HIV. Fortunately, it can be prevented. The main ways to prevent HIV infection are:

  • using condoms during sex (including vaginal, oral, and anal sex)
  • having fewer sexual partners
  • not sharing needles or other equipment to take illicit drugs

Unless you are in a mutually monogamous relationship (neither of you is having sex with anyone else), and you are sure neither of you is HIV-positive, make sure to use a condom every time you have sex. In some cases, couples where one partner is infected may decide to risk infection of the other partner, especially if they are trying to get pregnant. If this is the case, talk to your doctor. Your choice of sexual partner is also important, since condoms do sometimes break or leak. You may know that you practice safe sex and that you haven't used dirty needles, but you must also know that your sexual partners and all their other partners do the same. Sharing needles is very dangerous – it carries a high risk of getting HIV.

People with other sexually transmitted infections (STIs) such as herpes are much more likely to contract HIV during sex, probably because of tiny breaks in their skin or vaginal lining. Keeping free of other STIs will help reduce your risk of HIV infection, but this alone will not protect you from infection. That's why it is important to use condoms.

If you have HIV and become pregnant, tell your doctor. The risk of infecting an infant during birth has been reduced dramatically through the use of medication and caesarean section when appropriate.